Integrated circuit device including vertical memory device and method of manufacturing the same

ABSTRACT

An integrated circuit (IC) device includes: a channel region that extends on the substrate to penetrate a plurality of word lines; a bit line contact pad that contacts an upper surface of the channel region; a bit line that contacts the bit line contact pad and extends on the bit line contact pad in a direction parallel to the main surface of the substrate; a common source line that partially fills a word line cut region and has a height lower than that of the channel region; and a common source via contact that contacts an upper surface of the common source line in the word line cut region.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 15/245,441, filed on Aug. 24, 2016, which claims priority under35 U.S.C. § 119 to Korean Patent Application No. 10-2016-0010725, filedon Jan. 28, 2016, in the Korean Intellectual Property Office, thedisclosure of which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

The inventive concept relates to an integrated circuit (IC) device and amethod of manufacturing the IC device, and more particularly, to an ICdevice including a nonvolatile vertical memory device and a method ofmanufacturing the IC device.

DISCUSSION OF RELATED ART

Large capacity and high integration of IC devices including memorydevices are features required to meet the demand for multifunctionalinformation and communication devices. The high integration of thememory devices with a reduction in memory cell sizes have made thosefunctions and features included in the memory devices such as operationsof memory devices, and structures of operational circuits andinterconnection lines, to become more complicated

SUMMARY

According to an aspect of the inventive concept, there is provided an ICdevice including: a plurality of word lines that extend on a substrateparallel to a main surface of the substrate and are separated from oneanother in a first direction perpendicular to the main surface; achannel region that extends in a first region on the substrate throughthe plurality of word lines; a bit line contact pad that is on thechannel region and contacts an upper surface of the channel region; abit line that contacts the bit line contact pad in the first region andextends on the bit line contact pad in a second direction parallel tothe main surface of the substrate; a common source line that partiallyfills a word line cut region, the word line cut region extending in athird direction on a side of the plurality of word lines, the thirddirection being parallel to the main surface of the substrate andintersecting the second direction, the common source line having aheight lower than that of the channel region; and a common source viacontact that contacts an upper surface of the common source line in theword line cut region and extends from the upper surface of the commonsource line in a direction away from the substrate.

According to another aspect of the inventive concept, there is providedan IC device including: a peripheral circuit on a substrate; asemiconductor layer on the peripheral circuit; a memory cell arrayregion on the semiconductor layer and overlapping the peripheral circuitin a vertical direction, the memory cell array region including aplurality of memory cell arrays and a common source line tab regionbetween adjacent two of the plurality of memory cell arrays; a pluralityof word lines that extend on the semiconductor layer, parallel to a mainsurface of the substrate, and are included in each of the plurality ofmemory cell arrays and separated from one another in a first directionperpendicular to the main surface of the substrate; a plurality ofchannel regions that extend on the semiconductor layer in the firstdirection, passing through the plurality of word lines; a plurality ofbit line contact pads that are on the plurality of channel regions tocontact the plurality of channel regions; a plurality of bit lines thatextend in a region separated from the common source line tab region, ina second direction parallel to the main surface of the substrate andcontact a plurality of bit line contact pads; a common source line thatpartially fills a word line cut region, the word line cut regionextending in a third direction on a side of the plurality of word lines,the third direction being parallel to the main surface of the substrateand intersecting the second direction, the common source line having aheight lower than that of the plurality of channel regions; and at leastone common source via contact that contacts an upper surface of thecommon source line in the common source line tab region and extends fromthe upper surface of the common source line in a direction away from thesubstrate.

According to another aspect of the inventive concept, there is provideda method of manufacturing an integrated circuit (IC) device, the methodincluding forming a structure in which a plurality of insulating layersand a plurality of preliminary gate layers are alternately stacked oneby one on a substrate. A plurality of channel holes penetrating thestructure may be formed. A plurality of channel regions may be formed ina plurality of first channel holes selected from the plurality ofchannel holes in a first region on the substrate, and a plurality ofdummy channel regions may be formed in a plurality of second channelholes selected from the plurality of channel holes in a second regionseparated from the first region on the substrate, followed by forming aword line cut region that exposes the plurality of preliminary gatelayers and penetrates the structure to extend in a linear shape in adirection parallel to the main surface of the substrate to pass thefirst region and the second region. The plurality of preliminary gatelayers exposed through the word line cut region may be substituted witha plurality of conductive layers. An insulating spacer that covers aninner sidewall of the word line cut region may be formed, followed byforming a common source line that fills only a lower portion of the wordline cut region, leaving a recess space in an upper portion of the wordline cut region. A word line cut region buried insulating layer may beformed in the recess space to cover the common source line in the recessspace. A via contact hole that penetrates the word line cut regionburied insulating layer may be formed in the second region. A commonsource via contact may be formed in the via contact hole to contact thecommon source line.

According to still another aspect of the inventive concept, there isprovided an IC device including: at least one ground select line, aplurality of word lines, and at least one string select linesequentially stacked on a substrate, extending parallel to a mainsurface of the substrate and being spaced apart from one another with aninsulating layer interposed between each separation in a first directionperpendicular to the main surface; a channel region extending in a firstregion on the substrate through the at least one ground select line, theplurality of word lines, and the at least one string select line; adummy channel region extending in a second region separated from thefirst region on the substrate through the at least one ground selectline, the plurality of word lines, and the at least one string selectline; a bit line contact pad deposited on the channel region andcontacting an upper surface of the channel region; a bit line contactingthe bit line contact pad in the first region and extending on the bitline contact pad in a second direction parallel to the main surface ofthe substrate; a common source line partially filling a word line cutregion, the word line cut region extending in a third direction on aside of the at least one ground select line, the plurality of wordlines, and the at least one string select line, the third directionbeing parallel to the main surface of the substrate and intersecting thesecond direction; a word line cut region buried insulating layerdeposited on the common source line in the word line cut region to fillup the word line cut region; a common source via contact surrounded bythe word line cut region buried insulating layer, contacting an uppersurface of the common source line in the word line cut region andextending from the upper surface of the common source line in adirection away from the substrate in the second region; a first upperwiring layer covering the bit line in the first region with an upperinsulating layer interposed therebetween; and a second upper wiringlayer formed at a level the same as that of the first upper wiring layerin the second region and being connected to the common source viacontact.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the inventive concept will be more clearly understoodfrom the following detailed description taken in conjunction with theaccompanying drawings in which:

FIGS. 1A to 1D are views illustrating an integrated circuit (IC) deviceaccording to an exemplary embodiment of the inventive concept, and inparticular, FIG. 1A is a plan view of main elements of the IC deviceaccording to an exemplary embodiment of the inventive concept, FIG. 1Bis a schematic perspective view of main elements in a region denoted by“1B” in FIG. 1A, FIG. 1C is a schematic vertical cross-sectional viewtaken along line C-C′ in FIG. 1A, and FIG. 1D is a schematic verticalcross-sectional view taken along line D-D′ in FIG. 1A;

FIG. 2 is an equivalent circuit diagram of a memory cell array (MCA) ina memory cell array region of an IC device according to an exemplaryembodiment of the inventive concept;

FIGS. 3A and 3B are cross-sectional views illustrating modificationexamples of gate dielectric layers that are applicable to the IC deviceaccording to an exemplary embodiment of the inventive concept;

FIGS. 4A to 4C are cross-sectional views illustrating various exemplarystructures of a word line cut region buried insulating layer of the ICdevice according to an exemplary embodiment of the inventive concept;

FIGS. 5A and 5B are views illustrating an IC device according to anexemplary embodiment of the inventive concept, and in particular, FIG.5A is a schematic cross-sectional view of a structure of a region of theIC device corresponding to the region taken along line C-C′ in FIG. 1A,and FIG. 5B is a schematic cross-sectional view of a structure of aregion of the IC device corresponding to the region taken along lineD-D′ in FIG. 1A;

FIGS. 6A and 6B are views illustrating an IC device according to anexemplary embodiment of the inventive concept, and in particular, FIG.6A is a schematic cross-sectional view of a structure of a region of theIC device corresponding to the region taken along line C-C′ in FIG. 1A,and FIG. 6B is a schematic cross-sectional view of a structure of aregion of the IC device corresponding to the region taken along lineD-D′ in FIG. 1A;

FIG. 7 is a planar layout diagram of main regions of an IC deviceaccording to an exemplary embodiment of the inventive concept;

FIGS. 8A to 8C are schematic views illustrating an IC device accordingto an exemplary embodiment of the inventive concept, and in particular,FIG. 8A is a schematic perspective view of main elements in a region ofthe IC device corresponding to the region “1B” of FIG. 1A, FIG. 8B is aschematic cross-sectional view of a portion of the IC devicecorresponding to the region taken along C-C′ in FIG. 1A, and FIG. 8C isa schematic cross-sectional view of a portion of the IC devicecorresponding to the region taken along D-D′ in FIG. 1A;

FIGS. 9A and 9B are cross-sectional views illustrating an IC deviceaccording to an exemplary embodiment of the inventive concept;

FIGS. 10A to 10J are cross-sectional views that sequentially illustratea method of manufacturing an IC device, according to an exemplaryembodiment of the inventive concept;

FIG. 11 is a schematic block diagram of a nonvolatile memory deviceusing an IC device according to an exemplary embodiment of the inventiveconcept; and

FIG. 12 is a block diagram of a mobile system using an IC deviceaccording to an exemplary embodiment of the inventive concept.

Since the drawings in FIGS. 1-12 are intended for illustrative purposes,the elements in the drawings are not necessarily drawn to scale. Forexample, some of the elements may be enlarged or exaggerated for claritypurpose.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, exemplary embodiments of the inventive concept will bedescribed in detail with reference to the accompanying drawings. Likereference numerals in the drawings denote like elements, and thus theirredundant description will be omitted.

It will be understood that, although the terms “first”, “second”,“third”, “fourth” etc. may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, a first element, component, region, layer or sectiondiscussed below could be termed a second element, component, region,layer or section, or vice versa, without departing from the teachings ofthe present inventive concept.

FIGS. 1A to 1D are views illustrating an integrated circuit (IC) device100 according to an exemplary embodiment of the inventive concept. Inparticular, FIG. 1A is a plan view of main elements of the IC device 100according to an exemplary embodiment of the inventive concept. FIG. 1Bis a schematic perspective view of main elements in a region denoted by“1B” in FIG. 1A. FIG. 1C is a schematic vertical cross-sectional viewtaken along line C-C′ in FIG. 1A. FIG. 1D is a schematic verticalcross-sectional view taken along line D-D′ in FIG. 1A.

Referring to FIGS. 1A to 1D, the IC device 100 includes a memory cellarray region 12 on a substrate 102.

The substrate 102 may have a main surface 102M extending in the Xdirection and the Y direction. The substrate 102 may include asemiconductor substrate or a semiconductor-on-insulator substrate. Thesubstrate 102 may include, for example, Si, Ge, or SiGe. In an exemplaryembodiment of the inventive concept, the substrate 102 may include, forexample, a silicon-on-insulator (SOI) substrate or agermanium-on-insulator (GeOI) substrate.

As illustrated in FIG. 1A, the memory cell array region 12 of the ICdevice 100 may include a plurality of memory cell arrays MCAs. A commonsource line tab region CSL TAB included in the memory cell array region12 may be between adjacent two of the plurality of memory cell arraysMCAs.

FIG. 2 is an equivalent circuit diagram of a memory cell array MCA inthe memory cell array region 12 of the IC device 100, and in particular,illustrates an equivalent circuit diagram of a NAND flash memory devicehaving a vertical channel structure. The NAND flash memory deviceillustrated is a non-planar and nonvolatile memory device.

Referring to FIG. 2, the memory cell array MCA may include a pluralityof memory cell strings MS. The memory cell array MCA may include aplurality of bit lines BL1, BL2, . . . , BLm (collectively denoted by“BL”), a plurality of word lines WL1, WL2, . . . , WLn−1, WLn(collectively denoted by “WL”), at least one string select line SSL, atleast one ground select line GSL, and a common source line CSL. Theplurality of memory cell strings MS may be between the plurality of bitlines BL1, BL2, . . . , BLm and the common source line CSL.

Each of the plurality of memory cell strings MS may include at least onestring select transistor SST, at least one ground select transistor GST,and a plurality of memory cell transistors MC1, MC2, . . . , MCn−1, andMCn. A drain region of the at least one string select transistor SST ofeach of the plurality of memory cell strings MS may be connected to eachof the bit lines BL1, BL2, . . . , BLm, and a source region of the atleast one ground select transistor GST of each of the plurality ofmemory cell strings MS may be connected to the common source line CSL.The common source line CSL may be a region connected in common withsource regions of the plurality of ground select transistors GST. Eachof the plurality of memory cell strings MS may be connected to each bitline of the bit lines BL1, BL2, . . . , BLm, respectively. However, forsome instances, two or more memory cell strings may be connected to thesame bit line of the bit lines BL1, BL2, . . . , BLm.

The at least one string select transistor SST may be connected to the atleast one string select line SSL, and the at least one ground selecttransistor GST may be connected to the at least one ground select lineGSL. The plurality of memory cell transistors MC1, MC2, . . . MCn−1, MCnmay be connected to the word lines WL1, WL2, . . . , WLn−1, WLn,respectively.

The memory cell array MCA may have a 3-dimensional structure. Aplurality of memory cell transistors MC1, MC2, . . . , MCn−1, MCn thatconstitute the memory cell strings MS may have a structure seriallyconnected to the main surface 102M (refer to FIGS. 1C and 1D) of thesubstrate 102 in a vertical direction (the Z direction in FIGS. 1A to1D). Accordingly, channel regions 180 (see FIGS. 1C and 1D) of the atleast one string select transistor SST, the at least one ground selecttransistor GST, and the plurality of memory cell transistors MC1, MC2, .. . , MCn−1, MCn may extend in a substantially vertical direction to themain surface 102M of the substrate 102.

Referring back to FIGS. 1A to 1D, in the memory cell array region 12,the plurality of word lines WL1, WL2, . . . , WLn−1, WLn may extendparallel to an extending direction of the main surface 102M of thesubstrate 102 and vertically overlap one another and may be separatedfrom one another in a vertical direction of the substrate 102. Theplurality of word lines WL1, WL2, . . . , WLn−1, WLn may be repeatedlydisposed while being separated from each other at regular intervals by aplurality of word line cut regions WLC in a first direction (the Xdirection in FIGS. 1A to 1D) that is parallel to an extending directionof the main surface 102M of the substrate 102. The plurality of wordline cut regions WLC may extend parallel to one another in a seconddirection (the Y direction in FIGS. 1A to 1C), which is parallel to theextending direction of the main surface 102M of the substrate 102 and isperpendicular to the first direction, while defining the width of theplurality of word lines WL1, WL2, . . . , WLn−1, WLn in the firstdirection (the X direction in FIGS. 1A to 1C) that is parallel to theextending direction of the main surface 102M of the substrate 102.

A plurality of common source regions 172 may extend in an extendingdirection (the Y direction in FIGS. 1A to 1C) of the word line cutregions WLC of the memory cell array MCA parallel to the main surface ofthe substrate 102 and in upper portions of the substrate 102. In anexemplary embodiment of the inventive concept, the plurality of commonsource regions 172 may be impurity regions highly doped with, forexample, n-type impurities. The n-type impurities may include, forexample, phosphorus, arsenic, antimony, or bismuth. The plurality ofcommon source regions 172 may have a conductive type that is differentfrom that of the substrate 102. The plurality of common source regions172 may serve as a source region that supplies current to verticalmemory cells.

The plurality of common source lines CSL may extend in the extendingdirection (the Y direction in FIGS. 1A to 1C) of the word line cutregions WLC on the common source regions 172. The plurality of commonsource lines CSL may partially fill the word line cut regions WLC onsidewalls of a pair of ground select lines GSL, the word lines WL1, WL2,. . . , WLn−1, WLn, and a pair of string select lines SSL. The pluralityof common source lines CSL may have a height lower than that of theplurality of channel regions 180. The plurality of common source linesCSL may have a sidewall facing the pair of string select lines SSL.

At least one ground select line GSL, a plurality of word lines WL1, WL2,. . . , WLn−1, WLn, and at least one string select line SSL may besequentially stacked between two adjacent word line cut regions WLC.

The at least one ground select line GSL, the plurality of word linesWL1, WL2, . . . , WLn−1, WLn, and the at least one string select lineSSL may each include, for example, metal, metal silicide, semiconductordoped with impurities, or a combination thereof. For example, the atleast one ground select line GSL, the plurality of word lines WL1, WL2,. . . , WLn−1, WLn, and the at least one string select line SSL may eachinclude metal, such as tungsten, nickel, cobalt, titanium, or tantalum;metal silicide, such as tungsten silicide, nickel silicide, cobaltsilicide, titanium silicide, or tantalum silicide; polysilicon dopedwith impurities; or a combination thereof. However, the inventiveconcept is not limited thereto.

Insulating layers 176 may be between the substrate 102 and the at leastone ground select line GSL, and between each neighboring two of the atleast one ground select line GSL, the plurality of word lines WL1, WL2,. . . , WLn−1, WLn, and the at least one string select line SSL. Theinsulating layers 176 may be formed of, for example, silicon oxide,silicon nitride, or silicon oxynitride. However, the inventive conceptis not limited thereto.

In the memory cell array MCA, the plurality of channel regions 180(refer to FIG. 1C) may pass through the at least one ground select lineGSL, the plurality of word lines WL1, WL2, . . . , WLn−1, WLn, the atleast one string select line SSL, and the plurality of insulating layers176 by extending in a direction (the Z direction) that is perpendicularto the main surface 102M of the substrate 102. The plurality of channelregions 180 may be separated from one another at regular intervals inthe X direction and the Y direction. The interval between twoimmediately neighboring channel regions 180 in the X direction may bethe same as or different from the interval between two immediatelyneighboring channel regions 180 in the Y direction. The arrangement ofthe plurality of channel regions 180 as illustrated in FIGS. 1A and 1Cis only an example, and may be modified or changed in various ways. Theplurality of channel regions 180 may be connected to the plurality ofbit lines BL, respectively.

A plurality of dummy channel regions 180D (refer to FIG. 1D) that arenot connected to a bit line BL may be formed in the common source linetab region CSL TAB. The plurality of dummy channel regions 180D may beformed at the same time with the plurality of channel regions 180 formedin the memory cell array MCA. The plurality of dummy channel regions180D and the plurality of channel regions 180 may have substantially thesame structure.

The plurality of channel regions 180 and the plurality of dummy channelregions 180D may be repeatedly formed at a constant pitch. The firstconstant pitch between the neighboring ones of the plurality of channelregions 180 and the neighboring ones of the plurality of dummy channelregions 180D in the X direction may be the same as or different from thesecond constant pitch between the neighboring ones of the plurality ofchannel regions 180 and the neighboring ones of the plurality of dummychannel regions 180D in the Y direction. In an exemplary embodiment ofthe inventive concept, the plurality of channel regions 180 and theplurality of dummy channel regions 180D may be arranged to form ahexagonal array.

In an exemplary embodiment of the inventive concept, the plurality ofchannel regions 180 and the plurality of dummy channel regions 180D mayinclude doped polysilicon and/or undoped polysilicon. The dopedpolysilicon may have n-type conductivity or p-type conductivity. In anexemplary embodiment of the inventive concept, the plurality of channelregions 180 and the plurality of dummy channel regions 180D may include,for example, metal, conductive metal nitride, silicide, carbon nanotube,graphene, or a combination thereof.

The plurality of channel regions 180 and the plurality of dummy channelregions 180D may each have a cylindrical shape. In an exemplaryembodiment of the inventive concept, a buried insulating layer 182 mayfill an internal space of each of the plurality of channel regions 180and the plurality of dummy channel regions 180D. Unlike the exemplaryembodiments of FIGS. 1C and 1D, the plurality of channel regions 180 andthe plurality of dummy channel regions 180D may have a pillar structure.In this case, the buried insulating layer 182 may not be formed.

A gate dielectric layer 184 may be between the plurality of channelregions 180 and the at least one ground select line GSL, the pluralityof word lines WL1, WL2, . . . , WLn−1, WLn, and the at least one stringselect line SSL, and between the plurality of dummy channel regions 180Dand the at least one ground select line GSL, the plurality of word linesWL1, WL2, . . . , WLn−1, WLn, and the at least one string select lineSSL.

The gate dielectric layer 184 may include a tunnel insulating layer, acharge storage layer, and a blocking insulating layer, sequentiallyformed on the sidewall of each of the channel regions 180. The tunnelinsulating layer may include, for example, silicon oxide, hafnium oxide,aluminum oxide, zirconium oxide, tantalum oxide, or the like. The chargestorage layer is a region in which electrons tunneling through thetunnel insulating layer from the plurality of channel regions 180 may bestored. The charge storage layer may include, for example, siliconnitride, boron nitride, silicon boron nitride, or impurity-dopedpolysilicon, or may include, for example, a quantum dot, a thin hafniumoxide on silicon oxide layer, graphene, or nano crystal. The blockinginsulating layer may include, for example, silicon oxide, siliconnitride, hafnium oxide, aluminum oxide, zirconium oxide, tantalum oxide,yttrium oxide, or a combination thereof. The blocking insulating layermay include a high-k dielectric material having a dielectric constanthigher than that of silicon oxide. In particular, the high-k dielectricmaterial may have a dielectric constant greater than the dielectricconstant of silicon nitride (e.g., k>7). In an exemplary embodiment ofthe inventive concept, the tunnel insulating layer, the charge storagelayer, and the blocking insulating layer may be formed by, for example,an atomic layer deposition (ALD) process, a chemical vapor deposition(CVD) process, etc.

FIGS. 1C and 1D illustrate an exemplary embodiment of the inventiveconcept, in which the gate dielectric layers 184 may have a shapeextending along the channel regions 180. The gate dielectric layer 184may surround an outer sidewall of the channel regions 180, and mayextend along the sidewall of the channel regions 180 to contact theupper surface of the substrate. However, the inventive concept is notlimited thereto.

FIGS. 3A and 3B are cross-sectional views illustrating structures ofgate dielectric layers 184A and 184B, instead of the gate dielectriclayer 184 of FIGS. 1C and 1D, applied to the IC device 100 according toan exemplary embodiment of the inventive concept.

In an exemplary embodiment of the inventive concept, the IC device 100according to the exemplary embodiment illustrated in FIGS. 1A to 1D mayinclude the gate dielectric layer 184A illustrated in FIG. 3A, insteadof the gate dielectric layer 184. The gate dielectric layer 184A mayhave a surface in contact with the channel region 180 and surfaces incontact with the insulating layers 176, and may cover lower and suppersurfaces and a sidewall of the word line WL. The gate dielectric layer184A may include a blocking insulating layer, a charge storage layer,and a tunnel insulating layer that are sequentially formed on the wordline WL.

In an exemplary embodiment of the inventive concept, the IC device 100according to the exemplary embodiment illustrated in FIGS. 1A to 1D mayinclude the gate dielectric layer 184B illustrated in FIG. 3B, insteadof the gate dielectric layer 184. The gate dielectric layer 184B may beformed between the word line WL and the channel region 180, but notbetween the word line WL and the insulating layers 176. The gatedielectric layer 184B may include a blocking insulating layer, a chargestorage layer, and a tunnel insulating layer that are sequentiallyformed in this stated order on the word line WL. The gate dielectriclayer 184B may cover only a sidewall of the word line WL, not the lowerand upper surfaces of the word line WL.

Detailed structures of the blocking insulating layer, the charge storagelayer, and the tunnel insulating layer of each of the gate dielectriclayers 184A and 184B of FIGS. 3A and 3B, respectively, may be the sameas those of the blocking insulating layer, the charge storage layer, andthe tunnel insulating layer of the gate dielectric layer 184 describedabove with reference to FIGS. 1A to 1D.

Structures and shapes of gate dielectric layers applicable to IC devicesaccording to the inventive concept are not limited only to the gatedielectric layers 184, 184A, and 184B illustrated in FIGS. 1C, 1D, 3A,and 3B and may be modified or changed in various ways within the scopeof the inventive concept.

In an exemplary embodiment of the inventive concept, the gate dielectriclayers 184, 184A, and 184B may include a material of which electricalresistance may be changed by heat generated due to the current passingthrough an adjacent electrode, for example, a phase change material. Thephase change material may include at least one of germanium (Ge),Gallium (Ga), antimony (Sb), tellurium (Te), and selenium (Se). Thephase change material may further include at least one impurity selectedfrom N, O, C, Bi, In, B, Sn, Si, Ti, Al, Ni, Fe, Dy, and La. The gatedielectric layers 184, 184A, and 184B may include, for example, GeBiTe,InSb, GeSb, GeSbTe, InSbTe, GaSb, GeSbTeN, GeSnSbTe, GeBiSbTe, orGeInSbTe. GeSbTe (germanium-antimony-tellurium or GST) is a phase-changematerial from the group of chalcogenide glasses, which may have acomposition represented by a formula such as, for example, Ge₁Sb₄Te₇,Ge₂Sb₂Te₅ or Ge₁Sb₂Te₄.

In an exemplary embodiment of the inventive concept, the gate dielectriclayers 184, 184A, and 184B may include a thin film structure of whichelectrical resistance may be changed using spin transfer by electriccurrent. For example, the gate dielectric layers 184, 184A, and 184B mayinclude a ferromagnetic material or an antiferromagnetic material.

In an exemplary embodiment of the inventive concept, the gate dielectriclayers 184, 184A, and 184B may include a perovskite compound or atransition metal oxide. For example, the gate dielectric layers 184,184A, and 184B may include niobium oxide, titanium oxide, nickel oxide,zirconium oxide, vanadium oxide, PCMO ((Pr,Ca)MnO₃), strontium-titaniumoxide, barium-strontium-titanium oxide, strontium-zirconium oxide,barium-zirconium oxide, or barium-strontium-zirconium oxide.

In an exemplary embodiment of the inventive concept, a barrier metallayer may be further formed between the gate dielectric layer 184 andany one of the at least one ground select line GSL, the plurality ofword lines WL1, WL2, . . . , WLn−1, WLn, and the at least one stringselect line SSL.

Referring back to FIGS. 1A to 1D, an insulating spacer 192 that covers asidewall of the common source line CSL may be formed in the word linecut region WLC. The insulating spacer 192 may electrically insulate theat least one ground select line GSL, the plurality of word lines WL1,WL2, . . . , WLn−1, WLn, the at least one string select line SSL, andthe common source line CSL from one another.

In an exemplary embodiment of the inventive concept, the common sourceline CSL may be formed of a metal such as, for example, tungsten,copper, aluminum, or the like; a conductive metal nitride such as, forexample, titanium nitride, tantalum nitride, or the like; a transitionmetal such as, for example, titanium, tantalum, or the like; a metalsilicide such as, for example, nickel silicide, titanium silicide,tungsten silicide, cobalt silicide, or the like; or a combinationthereof. However, the material of the common source line CSL is notlimited to the above-listed examples.

In an exemplary embodiment of the inventive concept, the insulatingspacer 192 may be formed of, for example, silicon oxide, siliconnitride, silicon oxynitride, or a low-dielectric material. Thelow-dielectric material may have a dielectric constant smaller than thedielectric constant of silicon oxide (e.g., k<3.9). For example, theinsulating spacer 192 may be formed of SiO₂, Si₃N₄, SiON, SiCOH, SiOCN,SiCN, or a combination thereof. In an exemplary embodiment of theinventive concept, the insulating spacer 192 may have a dielectricconstant of about 4 to 6, but is not limited thereto.

The ground select line GSL, some of the channel regions 180 adjacent tothe ground select line GSL, and some gate dielectric layers 184 mayconstitute the ground select transistor GST illustrated in FIG. 2. Theplurality of word lines WL1, WL2, . . . , WLn−1, WLn, some of thechannel regions 180 adjacent to the plurality of word lines WL1, WL2, .. . , WLn−1, WLn, and some of the gate dielectric layers 184 mayconstitute the plurality of memory cell transistors MC1, MC2, . . . ,MCn−1, MCn illustrated in FIG. 2. The string select line SSL, some ofthe channel regions 180 adjacent to the string select line SSL, and somegate dielectric layers 184 may constitute the string select transistorSST illustrated in FIG. 2.

A plurality of bit line contact pads 186 may be formed on the pluralityof channel regions 180. The plurality of bit line contact pads 186 maydirectly contact upper surfaces of the corresponding channel regions180, respectively. The plurality of bit line contact pads 186 may serveas drain regions.

In an exemplary embodiment of the inventive concept, the plurality ofbit line contact pads 186 may be formed of, for example, animpurity-doped polysilicon, a metal, a conductive metal nitride, or acombination thereof. Examples of the metal for forming the plurality ofbit line contact pads 186 are tungsten, nickel, cobalt, tantalum, or thelike, but are not limited thereto.

A plurality of bit lines BL may be formed on the plurality of bit linecontact pads 186. As illustrated in FIG. 1C, the plurality of bit linesBL may directly contact the upper surfaces of the plurality of bit linecontact pads 186, respectively. The plurality of bit lines BL may extendin a direction (the X direction) parallel to the main surface 102M ofthe substrate 102. A plurality of drain regions of the string selecttransistors SST of the plurality of memory cell strings MS may beconnected to the plurality of bit lines BL through the plurality of bitline contact pads 186.

As illustrated in FIG. 1C, the plurality of channel regions 180 formedto penetrate the at least one ground select line GSL, the plurality ofword lines WL, the at least one string select line SSL, may be connectedto the plurality of bit lines BL via the bit line contact pads 186. Inan exemplary embodiment of the inventive concept, the plurality of bitlines BL may be formed of, for example, an impurity-doped polysilicon, ametal, a conductive metal nitride, or a combination thereof. Examples ofthe metal for forming the plurality of bit lines BL are tungsten,nickel, cobalt, tantalum, or the like, but are not limited thereto.

As illustrated in FIG. 1D, a plurality of dummy contact pads 186D may beformed on the plurality of dummy channel regions 180D, respectively. Theplurality of dummy contact pads 186D may have a structure substantiallythe same as that of the plurality of bit line contact pads 186, exceptthat the plurality of dummy contact pads 186D may not be connected tothe bit lines BL.

A planar layout of the plurality of bit line contact pads 186 and theplurality of dummy contact pads 186D is illustrated in FIG. 1A. Asillustrated in FIG. 1A, the plurality of bit line contact pads 186 andthe plurality of dummy contact pads 186D may be arranged to form ahexagonal array.

The plurality of channel regions 180 and the plurality of dummy channelregions 180D may be arranged under the plurality of bit line contactpads 186 and the plurality of dummy contact pads 186D, respectively, tohave structures the same planar arrangement as those of the plurality ofbit line contact pads 186 and the plurality of dummy contact pads 186D,respectively. Although FIG. 1 illustrates the arrangement of theplurality of bit line contact pads 186 and the plurality of dummycontact pads 186D as hexagonal arrays, the inventive concept is notlimited to the exemplary embodiment of FIG. 1A. For example, theplurality of bit line contact pads 186, the plurality of dummy contactpads 186D, the plurality of channel regions 180 under the plurality ofbit line contacts 186, and the plurality of dummy channel regions 180Dunder the plurality of dummy contact pads 186D may be arranged in amatrix array.

A first height H11 of the common source line CSL in each of the wordline cut regions WLC may be less than a total height of the word linecut region WLC. As used herein, the total height of a word line cutregion WLC may be defined as a vertical distance from the main surface102M of the substrate 102 to the bottom of the bit line BL. The verticaldistance refers to a distance in a direction perpendicular to the mainsurface 102M of the substrate 102.

In an exemplary embodiment of the inventive concept, the first heightH11 of the common source line CSL in the word line cut region WLC may beless than a second height H12 of the plurality of channel regions 180and a third height H13 of the plurality of dummy channel regions 180D.As illustrated in FIGS. 1C and 1D, a first level LV11 of the uppersurface of the common source line CSL may be lower than a second levelLV12 of the lower surface of the plurality of bit line contact pads 186and a third level LV13 of the lower surface of the plurality of dummycontact pads 186D, and may be higher than a fourth level LV14 of theupper surface of one of the string select lines SSL that is farthestfrom the substrate 102. However, the first height H11 of the commonsource line CSL and the first level LV11 of the upper surface of thecommon source line CSL are not limited to those illustrated in FIGS. 1Cand 1D. For example, the first level LV11 of the upper surface of thecommon source line CSL and the first height H11 thereof may be freelyselected within a range in which the first level LV11 of the uppersurface of the common source line CSL is lower than a level of the uppersurface of the plurality of channel regions 180. Since the plurality ofbit line contact pads 186 are on the plurality of channel regions 180 tocontact the plurality of channel regions 180, the level of the uppersurface of the plurality of channel regions 180 is the second level LV12of the lower surface of the plurality of bit line contact pads 186. Thatis, the first level LV11 may be freely selected within a range in whichthe first level LV11 is lower than the second level LV12.

A word line cut region buried insulating layer 194 may be formed on thecommon source line CSL and the insulating spacer 192 in the word linecut region WLC. In an exemplary embodiment of the inventive concept, theword line cut region buried insulating layer 194 may contact the uppersurfaces of the common source line CSL and the insulating spacer 192 inthe word line cut region WLC.

FIGS. 4A to 4C are cross-sectional views illustrating various exemplarystructures of the word line cut region buried insulating layer 194 ofthe IC device 100 described with reference to FIGS. 1A to 1D.

In an exemplary embodiment of the inventive concept, the word line cutregion buried insulating layer 194 may include a single layer, asillustrated in FIG. 4A. The word line cut region buried insulating layer194 may cover the upper surfaces of the common source line CSL and theinsulating spacer 192 in the word line cut region WLC. For example, theword line cut region buried insulating layer 194 may be formed of, forexample, silicon oxide, silicon nitride, silicon oxynitride, or alow-dielectric material. The low-dielectric material may have adielectric constant smaller than the dielectric constant of siliconoxide (e.g., k<3.9), and may include, for example, fluorine dopedsilicon oxide (F—SiO₂, k=3.6-3.8), carbon doped silicon oxide (SiCOH,k=2.7-3.0), or porous carbon doped silicon oxide (P—SiCOH, k=2.4 orbelow). For example, the word line cut region buried insulating layer194 may be formed of SiO₂, Si₃N₄, SiON, SiOCN, SiCOH, or SiCN. In anexemplary embodiment of the inventive concept, the word line cut regionburied insulating layer 194 may have a dielectric constant of about 4 toabout 6. However, the inventive concept is not limited thereto.

The word line cut region buried insulating layer 194 may extend in the Ydirection parallel to the common source line CSL in the word line cutregion WLC.

In an exemplary embodiment of the inventive concept, the word line cutregion buried insulating layer 194 may include a multi-layer structure,for example, a first insulating layer 194A and a second insulating layer194B that are formed of different materials.

The first insulating layer 194A may extend in the Y direction parallelto the common source line CSL, while covering opposite sidewalls of thesecond insulating layer 194B in the word line cut region WLC. The secondinsulating layer 194B may extend in the Y direction parallel to thecommon source line CSL in the word line cut region WLC.

In an exemplary embodiment of the inventive concept, the firstinsulating layer 194A may be formed of silicon nitride or siliconoxynitride, and the second insulating layer 194B may be formed ofsilicon oxide. In an exemplary embodiment of the inventive concept, thefirst insulating layer 194A and the second insulating layer 194B mayinclude different material layers, for example, materials selected fromSiO₂, Si₃N₄, SiON, SiOCN, SiCOH, and SiCN. However, materials forforming the first insulating layer 194A and the second insulating layer194B are not limited to the above-listed materials.

In an exemplary embodiment of the inventive concept, the word line cutregion buried insulating layer 194 may include a double layer includinga third insulating layer 194C and a fourth insulating layer 194D thatare formed of different materials.

The third insulating layer 194C may extend in the Y direction parallelto the common source line CSL, while covering both sidewalls and thelower surface of the fourth insulating layer 194D in the word line cutregion WLC. The fourth insulating layer 194D may extend in the Ydirection parallel to the common source line CSL in a space defined bythe third insulating layer 194C. The fourth insulating layer 194D may beseparated from the common source line CSL with the third insulatinglayer 194C therebetween.

In an exemplary embodiment of the inventive concept, the thirdinsulating layer 194C may be formed of silicon nitride or siliconoxynitride. The fourth insulating layer 194D may be formed of siliconoxide. In an exemplary embodiment of the inventive concept, the thirdinsulating layer 194C and the fourth insulating layer 194D may be formedof different materials, for example, materials selected from SiO₂,Si₃N₄, SiON, SiOCN, SiCOH, and SiCN. However, materials for forming thethird insulating layer 194C and the fourth insulating layer 194D are notlimited to the above-listed materials.

Embodiments of the word line cut region buried insulating layer 194including as a single layer or as a double layer are described withreference to FIGS. 4A to 4C. However, the inventive concept is notlimited thereto. For example, the word line cut region buried insulatinglayer 194 may include a multi-layer structure including more than twoinsulating layers of different materials, for example, a triple layer ora quadruple layer.

A width of the word line cut region buried insulating layer 194 in the Xdirection parallel to the extending direction of the plurality of bitlines BL may be greater than the width of the common source line CSL.

Referring back to FIGS. 1A to 1D, a plurality of common source viacontacts 198 (refer to FIG. 1D) may be formed on the common source linesCSL in the word line cut region WLC, respectively.

The plurality of common source via contacts 198 may contact the commonsource lines CSL, respectively, in the common source line tab region CSLTAB. The plurality of common source via contacts 198 may pass throughthe word line cut region buried insulating layer 194, a first upperinsulating layer 195, and a second upper insulating layer 196 in adirection away from the substrate 102. Accordingly, the plurality ofcommon source via contacts 198 may protrude from internal space in theword line cut region WLC. A distance from the substrate 102 to the uppersurface of the common source via contact 198 may be greater than thedistance from the substrate 102 to the upper surface of the bit linecontact pad 186 and the distance from the substrate 102 to the uppersurface of the bit lines BL.

The common source line CSL may have a linear shape extending along adirection parallel to the main surface 102M of the substrate 102 in theword line cut region WLC, while the plurality of common source viacontacts 198 may have a plug shape extending in some of the localregions on the upper surface of the common source line CSL, in adirection (the Z direction) perpendicular to the substrate 102.

The plurality of common source via contacts 198 may each be surroundedby a word line cut region buried insulating layer 194 in the word linecut region WLC of the common source line tab region CSL TAB.

In an exemplary embodiment of the inventive concept, the plurality ofcommon source via contacts 198 may be formed of, for example, a metal, ametal silicide, an impurity-doped semiconductor, or a combinationthereof. For example, the plurality of common source via contacts 198may include a metal, such as tungsten, nickel, cobalt, titanium,tantalum, or the like; a metal silicide, such as tungsten silicide,nickel silicide, cobalt silicide, titanium silicide, tantalum silicide,or the like; an impurity-doped polysilicon; or a combination thereof.However, the inventive concept is not limited thereto.

The first upper insulating layer 195 may have a plurality of line-shapedopenings that are filled with the plurality of bit lines BL,respectively. The second upper insulating layer 196 may extend to coverthe plurality of bit lines BL. The plurality of common source viacontacts 198 may extend through a plurality of via contact holes 198H(see FIG. 10I) formed through the second upper insulating layers 196.

The IC device 100 described with reference to FIGS. 1A to 1D may have areduced number of wiring layers on the plurality of bit lines BL in thememory cell array region 12. In particular, the number of wiring layersformed on the plurality of bit lines BL may be reduced to just one.Accordingly, the manufacturing process of the IC device 100 may besimplified. Since the number of metal wiring layers in the memory cellarray region 12 may be reduced, physical stress on the IC device causedfrom metal wires may be reduced, consequentially preventing warpage ofthe substrate 102. Physical stress created may cause dislocation defectin the semiconductor substrate, and may cause wafer warpage or evenwafer cracking. Due to the inclusion of the common source lines CSLpartially filling the word line cut regions WLC of the memory cell arrayregion 12, the volume of metal in the word line cut regions WLC may bereduced. Accordingly, physical stress on the IC device 100 may bereduced, so that deformation of the IC device 100, caused by physicalstress, and consequential occurrence of unwanted defects may beprevented.

FIGS. 5A and 5B are views illustrating an IC device 200 according to anexemplary embodiment of the inventive concept. In particular, FIG. 5A isa schematic cross-sectional view of a structure of a region of the ICdevice 200 corresponding to the region taken along line C-C′ in FIG. 1A.FIG. 5B is a schematic cross-sectional view of a structure of a regionof the IC device 200 corresponding to the region taken along line D-D′in FIG. 1A.

The IC device 200 illustrated in FIGS. 5A and 5B may have structuressubstantially the same as those of the IC device 100 of FIGS. 1A to 1D,except that the IC device 200 may include common source lines CSL2having a first height H21 less than the first height H11 (refer to FIGS.1C and 1D) of the common source lines CSI, illustrated in FIGS. 1A to1D, and word line cut region buried insulating layers 294 having aheight 294H greater than the height of the word line cut region buriedinsulating layers 194.

In an exemplary embodiment of the inventive concept, the first heightH21 of the common source lines CSL2 of the IC device 200 may be lessthan two thirds (⅔) of a total height of the word line cut regions WLCdefined as the vertical distance from the main surface 102M of thesubstrate 102 to the lower surface of the bit lines BL. The height 294Hof the word line cut region buried insulating layer 294 may be greaterthan one third (⅓) of the total height of the word line cut regions WLC.In an exemplary embodiment of the inventive concept, the first heightH21 of the common source lines CSL2 in the IC device 200 may be lessthan half (½) of the total height of the word line cut regions WLC, andthe height 294H of the word line cut region buried insulating layer 294may be greater than half (½) of the total height of the word line cutregions WLC. However, the first height H21 of the common source lineCSL2 and the height 294H of the word line cut region buried insulatinglayer 294 are not limited to the above.

The first height H21 of the common source lines CSL2 in the word linecut regions WLC may be less than a second height H12 of the plurality ofchannel regions 180 and a third height H13 of the plurality of dummychannel regions 180D. A first level LV21 of the upper surface of thecommon source lines CSL2 may be lower than a second level LV12 of thelower surface of the plurality of bit line contact pads 186 and a thirdlevel LV13 of the lower surface of the plurality of dummy contact pads186D, and lower than a fifth level LV25 of the lower surface of one ofthe string select lines SSL that is closest to the substrate 102. Sincethe plurality of bit line contact pads 186 are on the plurality ofchannel regions 180 to contact the plurality of channel regions 180, thelevel of the upper surface of the plurality of channel regions 180 isthe second level LV12 of the lower surface of the plurality of bit linecontact pads 186. Since the plurality of dummy contact pads 186D are onthe plurality of dummy channel regions 180D to contact the plurality ofdummy channel regions 180D, the level of the upper surface of theplurality of dummy channel regions 180D is the third level LV13 of thelower surface of the plurality of bit line contact pads 186. That is,the first level LV21 of the upper surface of the common source linesCSL2 may be lower than a second level LV12 of the upper surface of theplurality of channel regions 180 and a third level LV13 of the uppersurface of the plurality of dummy channel regions 180D. The word linecut region buried insulating layers 294 may have a sidewall facing apair of string select lines SSL.

In the IC device 200 illustrated in FIGS. 5A and 5B, the height of thecommon source lines CSL formed in the word line cut regions WLC of thememory cell array region 12 may be less than half (½) the total heightof the word line cut regions WLC, so that the volume of metal in theword line cut regions WLC may be markedly reduced, and consequentially,physical stress on the IC device 100 may also be markedly reduced.

FIGS. 6A and 6B are views illustrating an IC device 300 according to anexemplary embodiment of the inventive concept. In particular, FIG. 6A isa schematic cross-sectional view of a structure of a region of the ICdevice 300 corresponding to the region taken along line C-C′ in FIG. 1A.FIG. 6B is a schematic cross-sectional view of a structure of a regionof the IC device 300 corresponding to the region taken along line D-D′in FIG. 1A.

The IC device 300 illustrated in FIGS. 6A and 6B may have structuressubstantially the same as those of the IC device 100 of FIGS. 1A to 1D,except that the IC device 300 may further include first and second upperwiring layers 310 and 320 disposed on the plurality of common source viacontacts 198 to be connected to the same.

The first and second upper wiring layers 310 and 320 may be at the samelevel on the substrate 102. The first upper wiring layer 310 may beformed on the plurality of channels regions 180 and may cover the bitlines BL, and the second upper wiring layer 320 may be formed on theplurality of dummy channel regions 180D and may contact the plurality ofcommon source via contacts 198. The second upper insulating layer 196may be interposed between the first upper wiring layer 310 and the bitlines BL in the memory cell array MCA.

In an exemplary embodiment of the inventive concept, the second upperwiring layer 320 may be formed only in the common source line tab regionCSL TAB. In an exemplary embodiment of the inventive concept, the firstupper wiring layer 310 and the second upper wiring layer 320 may beseparated from one another.

In an exemplary embodiment of the inventive concept, the first upperwiring layer 310 and the second upper wiring layer 320 may beinterconnected as a single body. For example, the first upper wiringlayer 310 and the second upper wiring layer 320 together may form onemetal wiring layer having a mesh-like planar structure.

FIG. 7 is a planar layout diagram of main regions of an IC device 400according to an exemplary embodiment of the inventive concept.

Referring to FIG. 7, the IC device 400 may include a memory cell arrayregion 412, a first peripheral circuit region 414, a second peripheralcircuit region 416, and a bonding pad region 418.

The memory cell array region 412 may include a plurality of memory cellarrays MCA and common source line tab regions CSI. TAB, which have thesame configuration as those illustrated in FIGS. 1A and 2.

The memory cell array region 412 may have a configuration substantiallythe same as that of the memory cell array region 12 described withreference to FIGS. 1A to 1D.

The first peripheral circuit region 414 and the second peripheralcircuit region 416 may include control units for controlling data inputto or data output from the memory cell array region 412. Peripheralcircuits for driving vertical memory cells included in the memory cellarray region 412 may be disposed in the first peripheral circuit region414 and the second peripheral circuit region 416.

The first peripheral circuit region 414 may vertically overlap thememory cell array region 412 and thus reduce a planar area of a chipincluding the IC device 400.

In an exemplary embodiment of the inventive concept, peripheral circuitsdisposed in the first peripheral circuit region 414 may be circuits thatprocess data, which are input to or output from the memory cell arrayregion 412, at high speed. For example, peripheral circuits disposed inthe first peripheral circuit region 414 may be a page buffer, a latchcircuit, a cache circuit, a column decoder, a sense amplifier, a datainput/output (I/O) circuit, or the like.

The second peripheral circuit region 416 may be disposed in a region onone side of the memory cell array region 412 not to overlap the memorycell array region 412 and/or the first peripheral circuit region 414.Peripheral circuits formed in the second peripheral circuit region 416may be, for example, a row decoder. In an exemplary embodiment of theinventive concept, unlike the illustration in FIG. 7, the secondperipheral circuit region 416 may be disposed under the memory cellarray region 412.

The bonding pad region 418 may be formed on another side of the memorycell array region 412. The bonding pad region 418 may be a region, forexample, in which interconnection lines connected to word lines ofvertical memory cells of the memory cell array region 412 are formed.

FIGS. 8A to 8C are schematic diagrams illustrating an IC device 500according to an exemplary embodiment of the inventive concept. The ICdevice 500 of FIGS. 8A to 8C may have a planar layout the same as thatof the IC device 400 of FIG. 7. In particular, FIG. 8A is a schematicperspective view of main elements in a region of the IC device 500corresponding to the region “1B” of FIG. 1A. FIG. 8B is a schematiccross-sectional view of a portion of the IC device 500 corresponding tothe region taken along C-C′ in FIG. 1A. FIG. 8C is a schematiccross-sectional view of a portion of the IC device 500 corresponding tothe region taken along D-D′ in FIG. 1A.

In the IC device 500 of FIGS. 8A to 8C, the memory cell array region 412may have a structure substantially the same as that of the memory cellarray region 12 of the IC device 100 illustrated in FIGS. 1A to 1D. InFIGS. 8A to 8C, like reference numerals as those in FIGS. 1A to 1Ddenote like elements, and thus detailed description thereof will beomitted.

Referring to FIGS. 8A to 8C, the IC device 500 includes a firstperipheral circuit region 414 formed at a first level on a substrate402, and a memory cell array region 412 formed at a second level on thesubstrate 402, in which the second level is higher than the first level.

The term “level” used herein means a height from the substrate 402 in avertical direction (the Z direction in FIGS. 8A to 8C). The first levelon the substrate 402 is closer to the substrate 402 than the secondlevel to the substrate 402.

In an exemplary embodiment of the inventive concept, the substrate 402may have a main surface 402M extending in the X direction and the Ydirection. Details of the substrate 402 may be substantially the same asthose of the substrate 102 described with reference to FIGS. 1A to 1D.

In the substrate 402, an active region AC for peripheral circuits may bedefined by a device isolation layer 104. A plurality of transistors TRof the first peripheral circuit region 414 may be formed on the activeregion AC of the substrate 402. The plurality of transistors TR may eachinclude a gate G, a gate insulating layer GD, and a source/drain regionSD. Opposite sidewalls of the gate G may be covered with an insulatingspacer 106, and an etch stop layer 108 may be formed on the gate G andthe insulating spacer 106. The etch stop layer 108 may include aninsulating material, such as, for example, silicon nitride or siliconoxynitride.

A plurality of interlayer insulating layers 112A, 112B, 112C, and 112Dmay be sequentially stacked on the etch stop layer 108. The plurality ofinterlayer insulating layers 112A, 112B, 112C, and 112D may include, forexample, silicon oxide, silicon nitride, or silicon oxynitride.

The first peripheral circuit region 414 may include a multilayer wiringstructure 114 that is electrically connected to the plurality oftransistors TR. The multilayer wiring structure 114 may be insulated bythe plurality of interlayer insulating layers 112A, 112B, 112C, and112D.

The multilayer wiring structure 114 may include a first contact 116A, afirst wiring layer 118A, a second contact 116B, a second wiring layer118B, a third contact 116C, and a third wiring layer 118C, which may besequentially stacked on the substrate 402 and be electrically connectedto each other. In an exemplary embodiment of the inventive concept, thefirst wiring layer 118A, the second wiring layer 118B, and the thirdwiring layer 118C may be formed of a conductive material, such as, forexample, metal, conductive metal nitride, metal silicide, or acombination thereof. For example, the first wiring layer 118A, thesecond wiring layer 118B, and the third wiring 118C may include aconductive material, such as tungsten, molybdenum, titanium, cobalt,tantalum, nickel, tungsten silicide, titanium silicide, cobalt silicide,tantalum silicide, or nickel silicide.

Although the multilayer wiring structure 114 in FIGS. 8B and 8C is atriple-layer wiring structure including the first wiring layer 118A, thesecond wiring layer 118B, and the third wiring layer 118C, the inventiveconcept is not limited thereto. For example, the multilayer wiringstructure 114 may be a multilayer wiring structure including two layersor four or more layers according to a layout of the first peripheralcircuit region 414 and a type and arrangement of the gate G.

A semiconductor layer 420 covering the plurality of interlayerinsulating layers 112A, 112B, 112C, and 112D may be formed on the firstperipheral circuit region 414. The memory cell array region 412 may beformed on the semiconductor layer 420. The memory cell array region 412may have a structure substantially the same as that of the memory cellarray region 12 of the IC device 100 described with reference to FIGS.1A to 1D.

The semiconductor layer 420 may be formed of, for example, Si, Ge, or acombination thereof. The semiconductor layer 420 may be formed of, forexample, an impurity-doped semiconductor or an undoped intrinsicsemiconductor. The impurity-doped semiconductor may be an n-typeimpurity doped semiconductor or a p-type impurity doped semiconductor.The semiconductor layer 420 may have, for example, a single crystallinestructure, an amorphous structure, or a polycrystalline structure.

A plurality of common source regions 472 may be formed in thesemiconductor layer 420. A detailed structure of the plurality of commonsource regions 472 is substantially the same as that of the plurality ofcommon source regions 172 described with reference to FIGS. 1A to 1D.

The plurality of common source regions 472 may be formed in thesemiconductor layer 420 by doping with impurities. As illustrated inFIGS. 8B and 8C, a depth of the plurality of common source regions 472may be substantially the same as the thickness of the semiconductorlayer 420. Accordingly, the bottom surfaces of the plurality of commonsource regions 472 may contact the uppermost interlayer insulating layerof the plurality of interlayer insulating layers 112A, 112B, 112C, and112D in the first peripheral circuit region 414. In an exemplaryembodiment of the inventive concept, the plurality of common sourceregions 472 may be impurity regions highly doped with, for example,n-type impurities. The n-type impurities may include, for example,phosphorus, arsenic, antimony, or bismuth. The plurality of commonsource regions 472 may have a conductive type that is different fromthat of the semiconductor layer 420. For example, the plurality ofcommon source regions 472 may have a p-type conductivity, while thesemiconductor layer 420 may have an n-type conductivity, or vice versa.

In the IC device 500, the memory cell array region 412 and the firstperipheral circuit region 414 may be electrically connected to oneanother via at least one connection plug extending in a verticaldirection (the Z direction). The at least one connection plug may beformed to penetrate at least some of the plurality of interlayerinsulating layers 112A, 112B, 112C, and 112D of the first peripheralcircuit region 414, and the semiconductor layer 420. Wiring structuresformed in the memory cell array region 412 by the at least oneconnection plug may be electrically connected with wiring structuresformed in the first peripheral circuit region 414.

The IC device 500 illustrated in FIGS. 8A to 8C may have a multilayerdevice structure in which a first level semiconductor device and asecond level semiconductor device having different functions may bestacked upon one another to overlap in a direction perpendicular to themain surface 402M of the substrate 402. Accordingly, the multilayerwiring structures on the plurality of common source lines CSL and theplurality of channel regions 180 in the memory cell array region 412 mayhave a smaller number of layers. This may prevent excessive densityincrease of wiring patterns of the multilayer wiring structures in thememory cell array region 412 and simplify the manufacturing process ofthe IC device. Due to the reduced number of layers of the multilayerwiring structure, physical stress caused from the metal wirings may alsobe reduced, thus preventing warpage of the substrate 402.

FIGS. 9A and 9B are cross-sectional views illustrating an IC device 600according to an exemplary embodiment of the inventive concept. In FIGS.9A and 9B, like reference numerals as those in FIGS. 1A to 1D denotelike elements, and thus detailed description thereof will be omitted.

The IC device 600 illustrated in FIGS. 9A and 9B may have a structuresubstantially the same as that of the IC device 100 illustrated in FIGS.1A to 1D, except that the plurality of memory cell arrays MCA in the ICdevice 600 may include a first string select transistor SST0 and asecond string select transistor SST1 having different thresholdvoltages. To implement the first string select transistor SST0 and thesecond string select transistor SST1 having different thresholdvoltages, a plurality of channel regions 680 may include a plurality ofdoped channel regions 682 that are locally doped at a dopingconcentration higher than that of the other regions of the plurality ofchannel regions 680. Similarly, in the common source line tab regionsCSL TAB, a plurality of dummy channel regions 680D may include aplurality of dummy doped channel region 682D that are locally doped at adoping concentration higher than that of the other regions in theplurality of dummy channel regions 680D. Due to this structure, a firststring select transistor SST0 and a second string select transistor SST1having different threshold voltages may be formed in the common sourceline tab regions CSL TAB. The first string select transistor SST0 andthe second string select transistor SST1 formed in the common sourceline tab region CSL TAB may not function as a transistor.

In the IC device 600 illustrated in FIGS. 9A and 9B, a plurality ofground select lines GSL and a plurality of word lines WL, which arebetween the plurality of common source regions 172 on the substrate 102and the plurality of bit lines BL over the substrate 102, may be used asgate electrodes of the plurality of ground select transistors GST andthe plurality of memory cell transistors MC1, MC2, . . . , MCn−1, MCn(refer to FIG. 2). First and second string select lines SSL0 and SSL1may be used as gate electrodes of the first and second string selecttransistors SST0 and SST1.

The first and second string select lines SSL0 and SSL1 may controlelectrical connection between the plurality of bit lines BL and theplurality of memory cell strings MS. The ground select lines GSL maycontrol electrical connection between the plurality of memory cellstrings MS and the plurality of common source lines CSL.

The first and second string select lines SSL0 and SSL1 shared by theplurality of memory cell strings MS may be connected to at least one ofthe first string select transistors SST0 and at least one of the secondstring select transistors SST1, respectively. A first string selecttransistor SST0 of one memory cell string MS and a second string selecttransistor SST1 of another adjacent memory cell string MS may becontrolled by one first string select line SSL0 or one second stringselect line SSL1. The first and second string select transistors SST0and SST1 controlled by the first or second string select line SSL0 orSSL1 may have different threshold voltages, and may perform differentoperations according to a voltage applied to the first or second stringselect line SSL0 or SSL1. Accordingly, one of the plurality of memorycell strings MS may be electrically connected to a bit line BL accordingto the voltage applied to the first or second string select line SSL0 orSSL1. In this manner, electrical connection between one memory cellstring selected from the plurality of memory cell strings MS and a bitline BL may be selectively controlled.

To implement the first and second string select transistor SST0 and SST1having different threshold voltages with the first and second stringselect lines SSL0 and SSL1, some channel regions 680 selected from theplurality of channel regions 680 and some dummy channel regions 680Dselected from the plurality of dummy channel regions 680D may belocally, i.e., only regions adjacent to the second string select lineSSL1, doped with impurity ions to form doped channel regions 682 anddummy doped channel regions 682D. Some channel regions 680 selected fromthe plurality of channel regions 680 and some dummy channel regions 680Dselected from the plurality of dummy channel regions 680D may belocally, i.e., only regions adjacent to the first string select lineSSL0, doped with impurity ions to form doped channel regions 682 anddummy doped channel regions 682D. Impurity ions doped in the dopedchannel regions 682 and the dummy doped channel regions 682D may ben-type or p-type impurities.

In an exemplary embodiment of the inventive concept, the other regionsin the plurality of channel regions 680 and the plurality of dummychannel regions 680D, except for the doped channel regions 682 and thedummy doped channel regions 682D, may be formed of an undoped intrinsicsemiconductor, for example, an undoped polysilicon. Thus, when theplurality of channel regions 680 and the plurality of dummy channelregions 680D include no doped channel region 682 and no dummy dopedchannel region 682D, respectively, the first and second string selecttransistors SST0 and SST1 may have substantially the same thresholdvoltage.

As described above, the regions of a channel region 680 and a dummychannel region 680D adjacent to the first string select line SSL0 mayhave a different impurity concentration from the regions adjacent to thesecond string select line SSL1. Accordingly, the first and second stringselect transistors SST0 and SST1 having different threshold voltages maybe implemented with the first and second string select lines SSL0 andSSL1 and the plurality of channel regions 680 penetrating the first andsecond string select lines SSL0 and SSL1.

To implement a configuration in which a first threshold voltage of thefirst string select transistor SST0 is higher than a second thresholdvoltage of the second string select transistor SST1, a doped channelregion 682 may be formed by doping an undoped channel region 680 withp-type impurities. Alternatively, the other regions of the plurality ofchannel regions 680 and the plurality of dummy channel regions 680D,except for the doped channel regions 682 and the dummy doped channelregions 682D may be formed of an n-type impurity doped semiconductor,and the doped channel regions 682 and the dummy doped channel regions682D may be formed of p-type impurity doped semiconductor. In this case,the plurality of channel regions 680 and the plurality of dummy channelregions 680D may include the doped channel regions 682 and the dummydoped channel regions 682D adjacent to the first or second string selectline SSL0 or SSL1, wherein channels of opposite conductivity types maybe formed in adjacent two of the doped channel regions 682 or the dummydoped channel regions 682D, respectively. The channel regions of thefirst and second string select transistors SST0 and SST1 formed,respectively, in a channel region 680 and a dummy channel region 680Dmay have opposite conductivity types, and the first and second stringselect transistor SST0 and SST1 may have a further increased differencein threshold voltage.

To implement a configuration in which the threshold voltage of a firststring select transistor SST0 is less than the threshold voltage of asecond string select transistor SST1, a doped channel region 682 may beformed by doping a channel region 680 with n-type impurities.

In an exemplary embodiment of the inventive concept, the thickness ofeach of the first and second string select lines SSL0 and SSL1 may bethe same as the thickness of each of the plurality of word lines WL. Inan exemplary embodiment of the inventive concept, the thickness of thefirst and second string select lines SSL0, SSL1 may be greater than thethickness of the plurality of word lines WL.

FIGS. 10A to 10J are cross-sectional views that sequentially illustratea method of manufacturing an IC device, according to an exemplaryembodiment of the inventive concept. In the current exemplaryembodiment, a method of manufacturing the IC device 100 illustrated inFIGS. 1A to 1D is described as an example. FIGS. 10A to 10Jschematically illustrate main elements in the regions of the IC device100 taken along lines C-C′ and D-D′, according to the manufacturingprocess.

Referring to FIG. 10A, after forming a device isolation layer fordefining an active region AC on a substrate 102, a plurality ofinsulating layers 176 and a plurality of preliminary gate layers PL arealternately stacked one by one on the substrate 102.

The plurality of insulating layers 176 may be formed of, for example,silicon oxide, silicon nitride, or silicon oxynitride. The plurality ofpreliminary gate layers PL, which includes a material different fromthat of the insulating layer 176, may be formed of, for example, siliconnitride, silicon carbide, or polysilicon. Each of the plurality ofpreliminary gate layers PL may be a preliminary layer or a sacrificiallayer for forming at least one ground selection line GSL, a plurality ofword lines WL1, WL2, . . . , WLn−1, WLn, and at least one stringselection line SSL in subsequent processes.

Referring to FIG. 10B, after forming a plurality of channel holes 180Hthat penetrate the plurality of insulating layers 176 and the pluralityof preliminary gate layers PL and extend in a direction (the Zdirection) which is perpendicular to an extending direction (the Xdirection) of the main surface 102M of the substrate 102, a gatedielectric layer 184, a channel region 180, a dummy channel region 180D,and a buried insulating layer 182 are formed in each of the plurality ofchannel holes 180H. In the process of forming the plurality of channelholes 180H, a first mask pattern may be formed on the top layer of theplurality of insulating layers 176, and then the plurality of insulatinglayers 176 and the plurality of preliminary gate layers PL may beanisotropically etched using the first mask pattern as an etching maskuntil the main surface 102M of the substrate 102 is exposed. The firstmask pattern may be a photoresist pattern, and may be formed through alithographic process.

The gate dielectric layer 184 may cover an inner sidewall of each of theplurality of channel holes 180H. The gate dielectric layer 184 mayinclude a blocking insulating layer, a charge storage layer, and atunnel insulating layer, sequentially formed on the sidewall of each ofthe plurality of channel holes 180H. In an exemplary embodiment of theinventive concept, the tunnel insulating layer, the charge storagelayer, and the blocking insulating layer may be formed by, for example,an atomic layer deposition (ALD) process, a chemical vapor deposition(CVD) process, etc.

The channel region 180 and the dummy channel region 180D may contactregions of the substrate 102 exposed at the bottom of the channel holes180H, and an outer surface of the channel region 180 may contact thegate dielectric layer 184. In an exemplary embodiment of the inventiveconcept, the channel region 180 and the dummy channel region 180D may beformed of impurity-doped polysilicon. The channel region 180 and thedummy channel region 180D may be formed by, for example, a chemicalvapor deposition (CVD) process, a low pressure CVD (LPCVD) process, oran atomic layer deposition (ALD) process. However, the inventive conceptis not limited thereto.

The buried insulating layer 182 may be formed by, for example, a CVDprocess, an LPCVD process, or an ALD process by using an insulatingmaterial, such as, for example, silicon oxide, silicon nitride, orsilicon oxynitride. The buried insulating layer 182 may include an airgap.

After forming an insulating layer 185, which covers upper surfaces ofthe channel region 180, the dummy channel region 180D, the buriedinsulating layer 182, and the gate dielectric layer 184, and forming aplurality of contact holes 185H, which expose the upper surfaces of thechannel region 180, the dummy channel region 180D, and the buriedinsulating layer 182, in the insulating layer 185, a plurality of bitline contact pads 186 and a plurality of dummy contact pads 186D areformed in the plurality of contact holes 185H. In the process of formingthe plurality of channel holes 185H, a second mask pattern, which mayhave a pattern the same as that of the first mask pattern, may be formedon the insulating layer 185, and then the insulating layer 185 may beanisotropically etched using the second mask pattern as an etching maskuntil the upper surfaces of the plurality of channel regions 180 and theplurality of dummy channel regions 180D are exposed.

The insulating layer 185 may be formed of, for example, silicon nitride,silicon oxide, or silicon oxynitride. The plurality of bit line contactpads 186 and the plurality of dummy contact pads 186D may be formed of,for example, impurity-doped polysilicon, metal, conductive metalnitride, or a combination thereof. Examples of the metal for forming theplurality of bit line contact pads 186 are tungsten, nickel, cobalt,titanium, tantalum, and the like. However, the inventive concept is notlimited thereto.

Referring to FIG. 10C, a plurality of word line cut regions WLC thatpenetrate the plurality of insulating layers 176 and the plurality ofpreliminary gate layers PL (see FIG. 10B) and expose the substrate 102are formed. In the process of forming the plurality of word line cutregions WLC, a third mask pattern may be formed on the insulating layer185, the plurality of bit line contact pads 186 and the plurality ofdummy contact pads 186D, and then the insulating layer 185, theplurality of insulating layers 176 and the plurality of preliminary gatelayers PL may be anisotropically etched using the third mask pattern asan etching mask until the main surface 102M of the substrate 102 isexposed.

A plurality of common source regions 172 are formed by implantingimpurity ions into the substrate 102 through the plurality of word linecut regions WLC, and the plurality of preliminary gate layers PL (seeFIG. 10C) are substituted with a plurality of ground select lines GSL, aplurality of word lines WL1, WL2, . . . , WLn−1, WLn, and a plurality ofstring select lines SSL.

When the plurality of preliminary gate layers PL are formed ofpolysilicon, a silicidation process may be performed on the plurality ofpreliminary gate layers PL to substitute the plurality of preliminarygate layers PL with the plurality of ground select lines GSL, theplurality of word lines WL1, WL2, . . . , WLn−1, WLn, and the pluralityof string select lines SSL. In this case, the plurality of ground selectlines GSL, the plurality of word lines WL1, WL2, . . . , WLn−1, WLn, andthe plurality of string select lines SSL may each be formed of, forexample, tungsten silicide, tantalum silicide, cobalt silicide, ornickel silicide.

In an exemplary embodiment of the inventive concept, after selectivelyremoving the plurality of preliminary gate layers PL (see FIGS. 10B and10C) that are exposed through the plurality of word line cut regionsWLC, to form a plurality of empty spaces, the plurality of groundselection lines GSL, the plurality of word lines WL1, WL2, . . . ,WLn−1, WLn, and the plurality of string select lines SSL may be formedby burying a conductive material in the plurality of empty spaces thatare formed between the plurality of insulating layers 176. The pluralityof preliminary gate layers PL may be selectively removed by a wetetching process. In this case, the plurality of ground select lines GSL,the plurality of word lines WL1, WL2, . . . , WLn−1, WLn, and theplurality of string select lines SSL may be formed by using a metalmaterial, such as, for example, tungsten, tantalum, cobalt, or nickel.However, the inventive concept is not limited thereto.

Referring to FIG. 10D, an insulating spacer 192 and a preliminary commonsource line PCSL may be formed in each of the plurality of word line cutregions WLC.

The insulating spacer 192 may be formed of, for example, silicon oxide,silicon nitride, silicon oxynitride, or a low-dielectric material. Forexample, the insulating spacer 192 may be formed of SiO₂, Si₃N₄, SiON,SiCOH, SiOCN, SiCN, or a combination thereof.

The preliminary common source lines PCSL may be formed of a conductivematerial. For example, the preliminary common source lines PCSL may beformed of a metal, such as tungsten, copper, aluminum, or the like; aconductive metal nitride such as titanium nitride, tantalum nitride, orthe like; a transition metal, such as titanium, tantalum, or the like;or a combination thereof.

In an exemplary embodiment of the inventive concept, a metal silicidelayer for lowering contact resistance may be interposed between thecommon source region 172 and the preliminary common source line PCSL.For example, the metal silicide layer may be formed of cobalt silicide,tungsten silicide, nickel silicide, or the like. However, the inventiveconcept is not limited thereto.

In an exemplary embodiment of the inventive concept, to form theinsulating spacer 192 in each of the plurality of word line cut regionsWLC, after an insulating layer covering the inner sidewall of theplurality of word line cut regions WLC is formed, the insulating layermay be etched back to expose the substrate 102 at the bottom of theplurality of word line cut regions WLC, thereby forming the insulatingspacer 192 as a part of the insulating layer remaining on the innersidewall of each of the plurality of word line cut regions WLC.

To form the preliminary common source lines PCSL, after a conductivematerial is deposited on the inner sides of the plurality of word linecut regions WLC and on the insulating layer 185 to fill the spacedefined by the insulating spacer 192 in the plurality of word line cutregions WLC, the conductive material on an outside of the plurality ofword line cut regions WLC may be removed by CMP or etching back toexpose the upper surface of the insulating layer 185, thereby to leavethe conductive material only inside the plurality of word line cutregions WLC.

Referring to FIG. 10E, the preliminary common source lines PCSL may bepartially removed by an etching process from the plurality of word linecut regions WLC to form a plurality of recess spaces RS in upperportions of the plurality of word line cut regions WLC, so that aplurality of common source lines CSL partially fill the plurality ofword line cut regions WLC only to a certain height level in the wordline cut regions.

The upper surfaces of the plurality of common source lines CSL may beexposed through the plurality of recess spaces RS in the plurality ofword line cut regions WLC.

In an exemplary embodiment of the inventive concept, the preliminarycommon source lines PCSL may be formed of a metal. In this case, bypartial removal of the preliminary common source lines PCSL from theinside of the plurality of word line cut regions WLC, the volume ofmetal in the plurality of word line cut regions WLC may be removed asmuch as the amount of the preliminary common source lines PCSL removed.This may reduce physical stress on the IC device caused by metal, sothat deformation of the IC device, caused by physical stress, andconsequential occurrence of unwanted defects may be prevented.

In an exemplary embodiment of the inventive concept, the preliminarycommon source lines PCSL may be formed of tungsten (W). In this case, abyproduct gas such as hydrogen fluoride (HF) may be generated during theprocess of forming the preliminary common source lines PCSL. Thebyproduct gases may remain in the plurality of word line cut regions WLCafter the formation of the preliminary common source lines PCSL. When afluorine (F)-containing gas remains in the plurality of word line cutregions WLC, the F-containing gas may be locally concentrated in theplurality of word line cut regions WLC thus to damage the preliminarycommon source lines PCSL consisting of W and/or the gate dielectriclayer 184, so that a defect such as electrical short between the commonsource lines CSL and the word lines WL may occur.

In the method of manufacturing an IC device, according to an exemplaryembodiment of the inventive concept, byproduct gases remaining in theplurality of word line cut regions WLC may be discharged out of theplurality of recess spaces RS through the plurality of recess spaces RS.In an exemplary embodiment of the inventive concept, to dischargebyproduct gases such as hydrogen fluoride (HF) remaining in theplurality of word line cut regions WLC, a thermal treatment process or avacuum pumping process may be used. The heat treatment process may beperformed at a temperature higher than room temperature, for example, atabout 600° C., under nitrogen atmosphere. In an exemplary embodiment ofthe inventive concept, the thermal treatment process may be performedin-situ with the process of forming the preliminary common source linesPCSL.

In an exemplary embodiment of the inventive concept, during the partialremoval of the preliminary common source lines PCSL from the pluralityof word line cut regions WLC, the insulating spacers 192 exposed in theupper portions of the plurality of word line cut regions WLC may also beremoved at the same time, thus to expose the sidewall of the insulatinglayer 185 in upper regions of the plurality of recess spaces RS, asillustrated in FIG. 10E.

In an exemplary embodiment of the inventive concept, during the partialremoval of the preliminary common source lines PCSL from the inside ofthe plurality of word line cut regions WLC, at least part of theinsulating spacer 192 exposed in the upper portions of the plurality ofword line cut regions WLC may remain, covering the sidewall of theplurality of word line cut regions WLC.

Referring to FIG. 10F, a plurality of word line cut region buriedinsulating layers 194 filling the plurality of recess spaces RS (seeFIG. 10E) may be formed.

The plurality of word line cut region buried insulating layers 194 maybe formed to have any of the structures of the word line cut regionburied insulating layers 194 illustrated in FIGS. 4A to 4C.

In an exemplary embodiment of the inventive concept, to form the wordline cut region buried insulating layers 194 having a single layerstructure as illustrated in FIG. 4A, after an insulating material isdeposited on the substrate 102 to fill the plurality of recess spacesRS, the deposited insulating layer may be partially removed by CMP oretching back to remain only within the plurality of recess spaces RS,exposing the upper surface of the insulating layer 185.

The insulating material may be, for example, SiO₂, Si₃N₄, SiON, SiCOH,SiOCN, or SiCN.

In an exemplary embodiment of the inventive concept, to form the wordline cut region buried insulating layers 194 as a double layer,including the first insulating layer 194A and the second insulatinglayer 194B formed of different materials, as illustrated in FIG. 4B,after a preliminary insulating layer for forming the first insulatinglayer 194A is formed in the plurality of recess spaces RS, thepreliminary insulating layer may be partially etched back to leave onlya portion of the preliminary insulating layer covering the innersidewall of the plurality of recess spaces RS as the first insulatinglayer 194A. Next, the other region of the plurality of recess spaces RSmay be filled with the second insulating layer 194B.

The preliminary insulating layer may be formed of, for example, SiO₂,Si₃N₄, SiON, SiCOH, SiOCN, or SiCN.

In an exemplary embodiment of the inventive concept, to form the wordline cut region buried insulating layer 194 as a double layer, includingthe third insulating layer 194C and the fourth insulating layer 194Dformed of different materials, as illustrated in FIG. 4C, after aninsulating liner conformally covering the inner wall of the plurality ofrecess spaces RS is formed, a buried insulating layer may be formed onthe insulating layer to fill the other region of the plurality of recessspaces RS. Next, the unnecessary portions of the insulating liner andthe buried insulating layer remaining outside the plurality of recessspaces RS may be removed to leave the insulating liner and the buriedinsulating layer only within the plurality of recess spaces RS. Theinsulating liner and the buried insulating layer remaining within theplurality of recess spaces RS may form the third insulating layer 194Cand the fourth insulating layer 194D, respectively.

The insulating liner and the buried insulating layer may be formed ofdifferent materials selected from SiO₂, Si₃N₄, SiON, SiCOH, SiOCN, andSiCN.

Referring to FIG. 10G, a plurality of bit lines BL connected to somechannel regions selected from the plurality of channel regions 180 maybe formed.

The plurality of bit lines BL may not be formed on the plurality ofdummy channel regions 180D.

To form the plurality of bit lines BL, after a first upper insulatinglayer 195 which covers the plurality of bit line contact pads 186, theplurality of dummy contact pads 186D, the plurality of word line cutregion buried insulating layer 194, and the insulating layer 185 areformed on the substrate 102, the first upper insulating layer 195 may bepartially removed to have a plurality of linear openings that expose theplurality of channel regions 180. Next, a plurality of bit lines BL thatfill the plurality of linear openings may be formed using a damasceneprocess. The plurality of bit lines BL may directly contact some channelregions 180 selected from the plurality of channel regions 180. In thedamascene process, the pattern of the plurality of bit lines BL is firstlithographically defined, for example using a fourth mask pattern toform the plurality of linear openings, in the first upper insulatinglayer 195, then metal is deposited to fill the resulting linear openingsand then excess metal is removed by means of CMP.

In an exemplary embodiment of the inventive concept, the first upperinsulating layer 195 may be formed of, for example, a silicon oxidelayer, a silicon nitride layer, a silicon oxynitride layer, or acombination thereof.

Referring to FIG. 10H, a second upper insulating layer 196 that coversthe plurality of bit lines BL and the first upper insulating layer 195may be formed on the substrate 102.

In an exemplary embodiment of the inventive concept, the second upperinsulating layer 196 may be formed of, for example, a silicon oxidelayer, a silicon nitride layer, a silicon oxynitride layer, or acombination thereof.

Referring to FIG. 10I, in the common source line tab region CSL TAB, thesecond upper insulating layer 196, the first upper insulating layer 195,and the plurality of word line cut region buried insulating layers 194may be partially removed to form a plurality of via contact holes 198Hthat expose the plurality of common source lines CSL.

The plurality of via contact holes 198H may be formed in a region thatdoes not overlap with the plurality of bit lines BL.

Referring to FIG. 10J, in the common source line tab region CSL TAB, aplurality of common source via contacts 198 that fill the plurality ofvia contact holes 198H may be formed.

The plurality of common source via contacts 198 may be formed using adamascene process. In the damascene process, the pattern of theplurality of common source via contacts 198 is first lithographicallydefined, for example using a fifth mask pattern, to form the pluralityof contact holes 198H through the second upper insulating layer 196, thefirst upper insulating layer 195, and the plurality of word line cutregion buried insulating layers 194, then metal is deposited to fill theplurality of contact holes 198H and then excess metal is removed bymeans of CMP. The plurality of common source via contacts 198 may beformed of, for example, metal, metal silicide, semiconductor doped withimpurities, or a combination thereof. For example, the plurality ofcommon source via contacts 198 may include a metal, such as tungsten,nickel, cobalt, titanium, tantalum, or the like; a metal silicide, suchas tungsten silicide, nickel silicide, cobalt silicide, titaniumsilicide, tantalum silicide, or the like; polysilicon doped withimpurities; or a combination thereof. However, the inventive concept isnot limited thereto.

The method of manufacturing the IC device 100 is described above withreference to FIGS. 10A to 10J, but IC devices having structures otherthan modifications or changes described above in the manufacturingprocesses with reference to FIGS. 10A to 10J may also be manufacturedwithin the scope of the inventive concept. For example, to manufacturethe IC device 200 illustrated as an exemplary embodiment in FIGS. 5A and5B, when partially removing the preliminary common source lines PCSL(see FIG. 10D) from the inside of the plurality of word line cut regionsWLC in the process of forming the plurality of common source lines CSLdescribed with reference to FIG. 10E, a plurality of deep recess spaceshaving a deeper depth than the plurality of recess spaces RS illustratedin FIG. 10E may be formed by increasing the amount of the preliminarycommon source lines PCSL being removed.

The word line cut region buried insulating layer 294 (see FIGS. 5A and5B) that fills the plurality of deep recess spaces may be formed in asimilar manner as described with reference to FIG. 10F, and a pluralityof common source via contacts 298 (see FIG. 5B) that are connected tothe plurality of common source lines CSL through the word line cutregion buried insulating layer 294 may be formed by performing theprocesses described with reference to FIGS. 10G to 10J.

In the manufacturing of the IC device 200 illustrated in FIGS. 5A and5B, by increasing the amount of the preliminary common source lines PCSLbeing removed to form a plurality of deep recess spaces having acomparative deep depth in the plurality of word line cut regions WLC,the volume of the metal layer in the plurality of word line cut regionsWLC may be further reduced, and consequentially physical stress causedfrom the metal in the IC device 200 may also be further reduced.Accordingly, deformation of the IC device, caused by physical stress,and consequential occurrence of unwanted defects may be prevented.

In the case where the preliminary common source lines PCSL are formed oftungsten (W), by increasing the amount of the preliminary common sourcelines PCSL being removed to form a plurality of deep recess spaceshaving a comparative deep depth in the plurality of word line cutregions WLC, the process of removing F-containing byproduct gases asdescribed above with reference to FIG. 10E may be more easily andefficiently performed. Accordingly, the damage of peripheral constituentelements caused by the F-containing gas that is locally concentrated inthe plurality of word line cut regions, or defects such as electricalshort between the common source lines CSL and the word lines WL may befurther effectively prevented.

To manufacture the IC device 300 illustrated as an exemplary embodimentin FIGS. 6A and 6B, after forming a plurality of common source viacontacts 198 by performing the processes described with reference toFIGS. 10A to 10J, the upper wiring layers 310 and 320 that are connectedto the common source via contacts 198 may be formed on the plurality ofcommon source via contacts 198 and the second upper insulating layers196.

In an exemplary embodiment of the inventive concept, to manufacture theIC device 500 illustrated in FIGS. 8A to 8C, the following processes maybe performed. First, the first peripheral circuit region 414 may beformed in a region on the substrate 401. As an exemplary method offorming the first peripheral circuit region 414, first, a trench 402Tmay be formed in the substrate 402. The trench 402T may then be buriedwith an insulating material such as silicon oxide to form a deviceisolation layer 104 that defines the active region AC. Next, a pluralityof ion implantation processes may be performed on the substrate 402 toform a p-well and a n-well for a peripheral circuit. The p-well for theperipheral circuit may be a region for forming an NMOS transistor, andthe n-well for the peripheral circuit may be a region for forming a PMOStransistor.

A gate dielectric layer GD for the peripheral circuit may be formed onthe substrate 402. Next, a gate G for the peripheral circuit may beformed on the gate dielectric layer GD. The gate G may be formed of, forexample, doped polysilicon, metal, or a combination thereof. Theinsulating spacer 106 may be formed on a sidewall of the gate G, and asource/drain region SD may be formed on both sides of the gate G in thesubstrate 402. The source/drain region SD for forming an NMOS transistormay be formed by implanting n-type impurities in the substrate 402. Thesource/drain region SD for forming a PMOS transistor may be formed byimplanting p-type impurities in the substrate 402. The source/drainregion SD may have a lightly doped drain (LDD) structure. Accordingly, aplurality of transistors each including the gate dielectric layer GD,the gate G, and the source/drain region SD may be formed.

The etch stop layer 108 may be formed on the plurality of transistors TRand the insulating spacer 106. The etch stop layer 108 may include aninsulating material selected from, for example, silicon nitride, siliconoxynitride, and a combination thereof.

The multilayer wiring structure 114, which includes the first contact116A, the first wiring layer 118A, the second contact 116B, the secondwiring layer 118B, the third contact 116C, and the third wiring layer118C, and a plurality of interlayer insulating layers 112A, 112B, 112C,and 112D that insulate the layers in the multilayer wiring structure 114from one another may be formed on the etch stop layer 108. In anexemplary embodiment of the inventive concept, the third wiring layer118C of the multilayer wiring structure 114 may be an uppermost wiringlayer.

While the first peripheral circuit region 414 is formed in a region ofthe substrate 402, at least part of the second peripheral circuit region416 described with reference to FIG. 7 may also be formed in anotherregion on the substrate 402.

The semiconductor layer 420 may be formed on the interlayer insulatinglayer 112D that covers the third wiring layer 118C as the upper mostwiring layer of the multilayer wiring structure 114.

Similar processes as described above with reference to FIGS. 10A to 10Jmay be performed to thereby form the IC device 500 illustrated as anexemplary embodiment in FIGS. 8A to 8C.

To manufacture the IC device 600 illustrated as an exemplary embodimentin FIGS. 9A and 9B, after performing the processes of forming the gatedielectric layer 184, the channel region 180, the dummy channel region180D, and the buried insulating layer 182 in each of the plurality ofchannel holes 180H (referring to FIG. 10B), before forming theinsulating layer 185 that covers the upper surfaces of these formedlayers or regions, in the state where the upper portions of theplurality of channel regions 180 and the upper portions of the pluralityof dummy channel regions 180D are exposed, a sixth mask pattern thatexposes some channel regions 180 selected from the plurality of channelregions 180 and some dummy channel regions 180D selected from theplurality of dummy channel regions 180D may be formed, and a process ofselectively implanting a desired type of impurity ions into the somechannel regions 180 and the some dummy channel regions 180D that areexposed through the sixth mask pattern used as an ion implantation maskmay be performed. This ion implantation process may be performed once ormultiple times depending on need, to thereby form the plurality of dopedchannel regions 682 in the plurality of channel regions 680, and theplurality of dummy doped channel regions 682D in the plurality of dummychannel regions 680D (referring to FIGS. 9A and 9B).

In the methods of manufacturing an IC device, according to theabove-described embodiments of the inventive concept, the number ofwiring layers that may be formed on the plurality of bit lines BL may bereduced. In particular, only one wiring layer may be formed on theplurality of bit lines BL, so that the manufacturing process of avertical memory device may be simplified.

Exemplary methods of manufacturing IC devices according to theembodiments of the inventive concept are described above. However, itwill be understood by those of ordinary skill in the art that IC deviceshaving structures other than the modifications or changes of the ICdevices 100, 200, 300, 400, 500, and 600 illustrated as examples inFIGS. 1A to 9B may be manufactured within the scope of the inventiveconcept.

FIG. 11 is a schematic block diagram of a nonvolatile memory device 900using an IC device according to an exemplary embodiment of the inventiveconcept.

Referring to FIG. 11, a NAND cell array 910 of the nonvolatile memorydevice 900 may be combined with a core circuit unit 920. For example,the NAND cell array 910 may include at least one of the IC devices 100,200, 300, 400, 500, and 600 described above with reference to FIGS. 1Ato 9B. The core circuit unit 920 may include a control logic 922, a rowdecoder 924, a column decoder 932, a sense amplifier 934, and a pagebuffer 936.

The control logic 922 may communicate with the row decoder 924, thecolumn decoder 932, and the page buffer 936. The row decoder 924 maycommunicate with the NAND cell array 910 through a plurality of stringselection lines SSL, a plurality of word lines WL, and a plurality ofground selection lines GSL. The column decoder 932 may communicate withthe NAND cell array 910 through a plurality of bit lines BL. The senseamplifier 934 may be connected to the column decoder 932 when a signalis output from the NAND cell array 910 and may not be connected to thecolumn decoder 932 when a signal is transmitted to the NAND cell array910.

The control logic 922 may transmit row address signals to the rowdecoder 924, and the row decoder 924 may decode the row address signalsand transmit decoded row address signals to the NAND cell array 910through the plurality of string selection lines SSL, the plurality ofword lines WL, and the plurality of ground selection lines GSL. Thecontrol logic 922 may transmit column address signals to the columndecoder 932 or the page buffer 936, and the column decoder 932 maydecode the column address signals and transmit decoded column addresssignals to the NAND cell array 910 through the plurality of bit linesBL. Output signals of the NAND cell array 910 may be transmitted to thesense amplifier 934 via the column decoder 932 and amplified by thesense amplifier 934, and the amplified output signals may be transmittedto the control logic 922 via the page buffer 936.

FIG. 12 is a block diagram of a mobile system 1200 using an IC deviceaccording to an exemplary embodiment of the inventive concept.

Referring to FIG. 12, the mobile system 1200 may include an applicationprocessor 1210, a connectivity unit 1220, a volatile memory device 1230,a nonvolatile memory system 1240, a user interface 1250, and a powersupply 1260.

The mobile system 1200 may be any mobile system, such as, for example, amobile phone, a smart phone, a personal digital assistant (PDA), aportable multimedia player (PMP), a digital camera, a music player, aportable game console, or a navigation system.

The application processor 1210 may perform applications providing, forexample, internet browsers, games, or videos. In an exemplary embodimentof the inventive concept, the application processor 1210 may include asingle core or a multi-core. For example, the application processor core1210 may include a multi-core, such as a dual-core, a quad-core, or ahexa-core. Also, the application processor 1210 may further include acache memory located in the inside or outside thereof.

The connectivity unit 1220 may communicate with an external device bywire or wireless. For example, the connectivity unit 1220 may performEthernet communication, near field communication (NFC), radio frequencyidentification (RFID) communication, mobile telecommunication, memorycard communication, or universal serial bus (USB) communication. Forexample, the connectivity unit 1220 may include a baseband chipset andmay support communication such as GSM, GPRS, WCDMA, HSxPA, and the like.

The volatile memory device 1230 may store data that are processed by theapplication processor 1210 or may operate as a working memory. Forexample, the volatile memory device 1230 may be implemented with dynamicrandom access memory (DRAM), static random access memory (SRAM), mobileDRAM, double data rate (DDR) synchronous DRAM (DDR SDRAM), low power DDR(LPDDR) SDRAM, graphic DDR (GDDR) SDRAM, Rambus DRAM (RDRAM), or amemory that is similar thereto.

The nonvolatile memory system 1240 may include a memory controller 1241and a nonvolatile memory device 1243 and may store a boot image forbooting the mobile system 1200. For example, the nonvolatile memorydevice 1243 may be implemented with electrically erasable programmableread-only memory (EEPROM), a flash memory, phase change random accessmemory (PRAM), resistance random access memory (RRAM), nano floatinggate memory (NFGM), polymer random access memory (PoRAM), magneticrandom access memory (MRAM), ferroelectric random access memory (FRAM),or a memory that is similar thereto. The nonvolatile memory device 1243may include any one of the IC devices 100, 200, 300, 400, 500, and 600described above with reference to FIGS. 1A to 9B.

The user interface 1250 may include one or more input devices, such as,for example, a keypad or a touch screen, and/or one or more outputdevices, such as, for example, a speaker or a display device.

The power supply may supply an operating voltage of the mobile system1200. The mobile system 1200 may further include a camera imageprocessor (CIS) and a storage device, such as, for example, a memorycard, a solid state drive (SSD), a hard disk drive (HDD), or a CD-ROM.

The mobile system 1200 may be mounted by using packages of varioustypes. For example, the mobile system 1200 may be mounted by usingpackages, such as package on package (PoP), ball grid array (BGA), chipscale package (CSP), plastic leaded chip carrier (PLCC), plastic dualin-line package (PDIP), die in waffle pack (DWP), die in wafer form(DWF), chip on board (COB), ceramic dual in-line package (CERDIP),plastic metric quad flat pack (MQFP), thin quad flat-pack (TQFP), smalloutline IC (SOIC), shrink small outline package (SSOP), thin smalloutline package (TSOP), thin quad flat-pack (TQFP), system in package(SIP), multi chip package (MCP), wafer-level fabricated package (WFP),and wafer-level processed stack package (WSP).

While the inventive concept has been particularly shown and describedwith reference to specific embodiments of the inventive concept thereof,it will be understood that various changes in form and details may bemade therein without departing from the spirit and scope of thefollowing claims.

What is claimed is:
 1. An integrated circuit (IC) device comprising: aperipheral circuit on a substrate; a semiconductor layer on theperipheral circuit; a memory cell array region on the semiconductorlayer and overlapping the peripheral circuit in a vertical direction,the memory cell array region comprising a plurality of memory cellarrays and a common source line tab region between adjacent two of theplurality of memory cell arrays; a plurality of word lines that extendon the semiconductor layer, parallel to a main surface of the substrate,and are included in each of the plurality of memory cell arrays andseparated from one another in a first direction perpendicular to themain surface of the substrate; a plurality of channel regions thatextend on the semiconductor layer in the first direction, passingthrough the plurality of word lines; a plurality of bit line contactpads that are on the plurality of channel regions to contact theplurality of channel regions; a plurality of bit lines that extend in aregion separated from the common source line tab region, in a seconddirection parallel to the main surface of the substrate and contact aplurality of bit line contact pads; a common source line that partiallyfills a word line cut region, the word line cut region extending in athird direction on a side of the plurality of word lines, the thirddirection being parallel to the main surface of the substrate andintersecting the second direction, the common source line having aheight lower than that of the plurality of channel regions; and at leastone common source via contact that contacts an upper surface of thecommon source line in the common source line tab region and extends fromthe upper surface of the common source line in a direction away from thesubstrate.
 2. The IC device of claim 1, wherein the IC device furthercomprises a pair of string select lines that extend parallel to theplurality of word lines on the plurality of word lines, the plurality ofchannel regions extend through the plurality of word lines and the pairof string select lines, and the plurality of channel regions eachcomprises a doped channel region in a region facing one of the pair ofstring select lines, the doped channel region being locally doped at adoping concentration higher than that of other region of each of theplurality of channel regions.
 3. The IC device of claim 2, wherein thecommon source line has a sidewall facing the pair of string selectlines.
 4. The IC device of claim 2, wherein a level of an upper surfaceof the common source line is lower than a level of a lower surface ofone of the pair of string select lines that is closest to the substrate.5. The IC device of claim 2, wherein the IC device further comprises aword line cut region buried insulating layer that covers the commonsource line in the word line cut region, and the word line cut regionburied insulating layer has a sidewall facing the pair of string selectlines.
 6. The IC device of claim 1, wherein the IC device furthercomprises: an insulating spacer that covers both sidewalls of the commonsource line in the word line cut region; and a word line cut regionburied insulating layer that covers the common source line and theinsulating spacer in the word line cut region, wherein a width of theword line cut region buried insulating layer in the second direction isgreater than a width of the common source line in the second direction.7. The IC device of claim 1, wherein the IC device further comprises aword line cut region buried insulating layer that covers the commonsource line in the word line cut region, and the at least one commonsource via contact is surrounded by the word line cut region buriedinsulating layer in the word line cut region.
 8. The IC device of claim1, wherein a distance from the substrate to an upper surface of thecommon source via contact is greater than a distance from the substrateto an upper surface of one of the plurality of bit lines.
 9. The ICdevice of claim 1, wherein the IC device further comprises: a pluralityof dummy channel regions that extend in the first direction, penetratingthe plurality of word lines in the common source line tab region; and aplurality of dummy contact pads that are formed on the plurality ofdummy channel regions to contact upper surfaces of the plurality ofdummy channel regions.
 10. The IC device of claim 1, wherein the ICdevice further comprises: an upper insulating layer that extends tocover the plurality of bit lines and has at least one contact holethrough which the at least one common source via contact penetrates; afirst upper wiring layer that covers the plurality of bit lines with theupper insulating layer interposed therebetween; and a second upperwiring layer that is formed at a level the same as that of the firstupper wiring layer in the common source line tab region and is connectedto the at least one common source via contact.
 11. An integrated circuit(IC) device comprising: at least one ground select line, a plurality ofword lines, and at least one string select line sequentially stacked ona substrate, extending parallel to a main surface of the substrate andbeing spaced apart from one another with an insulating layer interposedbetween each separation in a first direction perpendicular to the mainsurface; a channel region extending in a first region on the substratethrough the at least one ground select line, the plurality of wordlines, and the at least one string select line; a dummy channel regionextending in a second region separated from the first region on thesubstrate through the at least one ground select line, the plurality ofword lines, and the at least one string select line; a bit line contactpad deposited on the channel region and contacting an upper surface ofthe channel region; a bit line contacting the bit line contact pad inthe first region and extending on the bit line contact pad in a seconddirection parallel to the main surface of the substrate; a common sourceline partially filling a word line cut region, the word line cut regionextending in a third direction on a side of the at least one groundselect line, the plurality of word lines, and the at least one stringselect line, the third direction being parallel to the main surface ofthe substrate and intersecting the second direction; a word line cutregion buried insulating layer deposited on the common source line inthe word line cut region to fill up the word line cut region; a commonsource via contact surrounded by the word line cut region buriedinsulating layer, contacting an upper surface of the common source linein the word line cut region and extending from the upper surface of thecommon source line in a direction away from the substrate in the secondregion; a first upper wiring layer covering the bit line in the firstregion with an upper insulating layer interposed therebetween; and asecond upper wiring layer formed at a level the same as that of thefirst upper wiring layer in the second region and being connected to thecommon source via contact.
 12. The IC device of claim 11, wherein thecommon source line has a height lower than a height of the channelregion, and the height of the common source line is less than two thirds(⅔) of a total height of the word line cut region.
 13. The IC device ofclaim 12, wherein the height of the common source line is less than onehalf (½) of the total height of the word line cut region.
 14. The ICdevice of claim 11, wherein material of the common source line includestungsten.